OK
Following the excellent responses from you guys, I will have to concede insurance is probably legally required, cos the chief executive says so (not actually legislated).
The relevant application of the requirement would likely come from:
12Advance notice of arrival, etc
(1)
The person in charge of a craft that is en route to New Zealand (from a point outside New Zealand) must, within the prescribed time, provide Customs with an advance notice of arrival, unless otherwise approved by the chief executive.
(2)
The